Art. 16. No person other than those specified in Article 12 shall during time of war be permitted to enter any such safety zone. It shall be lawful for the purposes of providing food, clothing and other necessaries of life to those within the zones for transport services (whether by land, sea or air) to proceed as far as the limits of the safety zone as indicated in the notification to other Powers, but not to enter within or fly over such limits, and to remain there for such period only as shall enable the articles transported to be unloaded. For such period as it is engaged upon or returning from such service, and provided it bears the same distinctive marks as those by which such safety zone is indicated, any railway, motor, steam or electric vehicle, ship or aircraft shall whilst within "x" kilometres of any part of the safety zone enjoy the same immunity as such safety zone, and such immunity shall extend to the road, permanent way, river or canal (so far as the same is within the said "x" kilometres of any part of the safety zone) along which such railway, vehicle or ship must necessarily travel in bringing supplies to or returning from the safety zone. No road, permanent way, river or canal which shall have been used for military purposes at any time whilst the safety zone existed as such shall be entitled to the immunity aforesaid.